Jablonski, S. and C. Bussler. Workflow Management: Modelling Concepts, Architecture and Implementation. Thomson Computer Press, London, 1996.
Patel
, D., Sutherland, J., Miller, J., (Eds.) Business
Object Design and Implementation II: OOPSLA'96, OOPSLA'97, and OOPSLA'98 Workshop
Proceedings. Springer, 1998.

Sutherland,
J.V. , Patel, D., Casanave, C., Miller, J., Hollowell, G., (Eds.) Business
Object Design and Implementation. Springer, 1997.
I have a few personal copies of the OOPSLA Business Object Workshop Proceedings that I will set at my cost. Send email.